Impact Resistance of a Cementitious Composite Foam Panel

ABSTRACT

A foam backed composite panel having two or more layers of materials adhesively bonded to each other. The panel is comprised of a cementitious material as a face layer and/or an optional core layer backed by polyurethane foam bonded to the face or core layer. The polyurethane foam bonds the panel to a supporting frame. The foam backed panel has increased impact and fire resistance.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.16/161,146 filed Oct. 16, 2018 and claims the benefit of the filingdates of U.S. Provisional Application Nos. 62/573,746, filed Oct. 18,2017 and 62/618,111, filed Jan. 17, 2018, which are incorporated hereinby reference.

INVENTION BACKGROUND

The inventive subject matter comprises the impact and fire resistance ofpolyurethane foam backed panels. Polyurethane foam backed panels arewell known primarily for the thermal insulating properties foam bringsto a wall or roof panel. Polyurethane foam has been sprayed into thecavities of framed walls and roofs and on top of roof substrates fordecades to provide a high quality building insulation.

Polyurethane foam backed panels have also been known to provide somedegree of flexural stiffness to a wall assembly. For example: U.S. Pat.No. 3,258,889 (Richard A. Butcher) discloses a structural wall comprisedof polyurethane foam bonded to an interior wallboard and to the sides ofstuds and teaches added stiffness of the framed wall to enable thinnerpanels and lighter frame members. U.S. Pat. No. 3,641,724 (James Palmer)discloses a wall section comprised of an exterior cover bonded to thesides of stud members by a polyurethane foam that increases the strengthof the entire structure. U.S. Pat. Nos. 4,748,781 & 4,914,883 (StanleyE. Wencley) discloses polyurethane fillets bonding a panel to framemembers to provide an increased strength bonded structure. U.S. Pat. No.5,736,221 (James S. Hardigg, et al) discloses two half panels with eachhaving a face and a web molded to the face's backside and the websbonded together to provide a panel having bending strength in alldirections.

More recently polyurethane foam backed panels with unique framesupported configurations have been shown to produce significantstructural qualities. For example US 20120011792 (Dean P. DeWildt et al)discloses a light-framed wall structure, comprised of sheathing attachedto studs with a top and bottom plate and spray polyurethane foam in thecavity, has high axial point, lateral and transverse load bearingproperties. In U.S. Pat. No. 9,919,499 I (Kenneth R. Kreizinger)disclosed a frame supported foam backed panel having substantialincreased load capacity derived from increasing the bonding strength ofthe polyurethane foam bonded to both a cladding and supporting framemembers. In pending US Application 20180202159 I disclosed thatindividual frame members of a supporting frame are greatly stiffenedwhen polyurethane foam, of a foam backed panel, is bonded to both thetop and the sides of frame members, i.e. is both continuous over a frameand in the frame's cavity.

However, no prior art teaches or even suggests that polyurethane foamcan also greatly increase the impact resistance of a cladding orsheathing to which it is bonded to create a foam backed panel. Inaddition, no prior art teaches or even suggests fire resistantstructural configurations for polyurethane foam backed panels. Finally,no prior art teaches a polyurethane foam backed sandwich panel with aninsulating refractory core material and polyurethane foam as one of thepanel's skin.

As such, one problem to be solved by this inventive matter is the use ofpolyurethane foam backing to increase a foam backed panel's impactresistance. A second problem to be solved is improving the fireresistance of polyurethane foam backed panels, since foam melts at arelatively low temperature, and thereby limits the foam's usefulness. Athird problem to be solved is foam backed panel configurations thatprevent polyurethane foam from melting when the face of the panels issubjected to fire.

SUMMARY OF INVENTION

The inventive subject matter comprises polyurethane foam backed panelswhich are defined as two or more layers of material(s) bonded togetherinto a composite panel with the backside layer being polyurethane foam.These panels have a face material, i.e. cladding, on the front side,optional core material layer(s) and polyurethane foam bonded to backsideof the face or to the backside of the last core material layer. Inessence the panel has a face on the front side and exposed polyurethanefoam on the backside. As such, the polyurethane foam backed panels maybe a sandwich panel with a face material on the front side, polyurethanefoam on the backside and a core comprised of any one or more materiallayers other than polyurethane foam.

Several improvements to a polyurethane foam backed panel have beendeveloped. First, when a sufficient thickness of polyurethane foam isbonded to the backside of certain claddings or sheathing, they have anincreased impact resistance. Second, compact “fire spacers” have beendeveloped to improve the fire resistance of foam backed panels and athird improvement is a panel configuration in which the core iscomprised of an insulating refractory material having substantialthermal resistance. Such a relatively thin panel core material canprevent substantial heat generated from a fire on the panel face fromreaching the polyurethane foam on the panel backside and thereby preventthe foam from melting.

Relative to greater impact resistance, it was found that despitepolyurethane foam's low compressive strength and hardness, typical twopound density, closed cell polyurethane foam bonded to the backside of acladding or sheathing greatly increases the impact resistance of thecladding or sheathing. The impact strength or toughness of a panel isdetermined by a falling, weighted object colliding into a stationarypanel and the panel's impact resistance determined by a visualcomparison of the impact damage done to a panel with polyurethane foambacking, to the impact damage to an identical panel without the foambacking.

The significance of polyurethane foam providing impact resistance isthat weaker, thinner and lighter claddings and sheathings can besubstituted for more expensive stronger, thicker and heavier materials.This provides a significant cost savings since polyurethane foam canalso provide insulation and an air, vapor and moisture barrier.

Relative to fire resistance, since polyurethane foam is known to melt ata relatively low temperature, improvements were sought to enable such apanel to resist fire. To this end, special fire spacers were developedfor insertion into a foam backed panel to enable the panel to resistfire, especially in applications where polyurethane foam provides thesole bond of the panel to a supporting frame. In such cases a claddingor sheathing will fall away from a building when fire melts thepolyurethane foam bonding them to the building's frame. To prevent this,refractory fire spacers were developed to provide a fire resistant bondbetween a refractory material layer and a building frame. Specifically,a refractory material such as magnesium phosphate can withstand 2,000°F. heat and flames and when used as a panel face or core layer that isbonded to a building frame by fire spacers, the magnesium phosphatelayer remains intact and in place while withstanding a fire for morethan an hour.

During development of the fire spacers, it was discovered that amagnesium phosphate binder can be combined with an insulating materialfiller to create an insulating refractory material capable ofwithstanding very high temperatures while also providing substantialthermal resistance. While such a material can be used as a foam backedpanel core material to protect the foam from melting, the use ofpolyurethane foam bonded to the backside of such a core material causesheat buildup at the core/foam joint. This heat buildup results frompolyurethane foam's much higher thermal resistance than that of theinsulating refractory material. As the heat flows through the insulatingrefractory material having a R-value of about 1, it encounters thepolyurethane foam having a R-value about six times greater, which causesthe heat to build-up and temperature to rise when reaching the foam.Despite this obstacle, it was found that about a one inch thickinsulating refractory core material provides sufficient thermalresistance, over a one hour test, to prevent polyurethane foam, on thecore's backside, from melting when a fire is applied to the core's frontside.

There were several unexpected results from the testing. First, it wasunexpected that bonding a weak foam insulating material to the backsideof a cladding or sheathing can substantially increase the cladding orsheathing's impact resistance. The advantage of such a finding is thatthinner claddings or sheathings may be used without sacrificing impactresistance or panels are much more impact resistance with a polyurethanefoam backing. This is especially advantageous since polyurethane foamperforms other functions such as providing thermal insulation andthereby results in a much more efficient utilization of materials andcost savings.

It was also unexpected that polyurethane foam bonded to the backside ofan insulating refractory core material caused heat to buildup after itpassed through the core. This resulted in requiring a slightly thickercore to further increase it's thermal resistance and prevent the foamfrom melting. Despite requiring a thicker core, it was unexpected tofind that as little as one inch thick insulating refractory materialcould provide the thermal resistance to reduce a 1700° F. heat appliedto a panel's face to only about 200° F. at the core's backside where athermal barrier existed. The advantage of such a finding is that itenables a simple, inexpensive foam backed panel to attain a one hourfire rating. For example a panel, comprised of a thin claddings such asa coating applied to only a one inch thick refractory material core andbacked by polyurethane foam bonding the core to a building frame, canattain a one hour fire rating.

It was also unexpected that fire spacers as small 2″×2″ can sufficientlybond a refractory material panel to frame members. The advantage of thisis that smaller fire spacers enable greater continuous foam for greaterinsulation. In addition fire spacers made of a refractory insulatingmaterial do not create an thermal bridge, although their thermalresistance is less than polyurethane foam.

It was also unexpected that refractory materials as thin as 0.25″ thickcan be used as a foam backed panel's face and/or core material to attaina one or more hour fire rating when bonded to a building frame with firespacers also made of refractory materials. The advantage of this is thatsuch refractory materials also provide a panel's cladding and/orsheathing and thereby result in a highly efficient utilization ofmaterials and cost savings. Another advantage is light weight fire ratedpanels.

It was also unexpected that precast foam backed panels may be cast,removed from a form and handled in as little as one hour and thatprecast foam backed panels may use a single binder in two or more layerswith each layer comprised of a different filler to product a differentmaterial properties.

Other objects, advantages and features of the inventive subject matterwill be self evident to those skilled in the art as more thoroughlydescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sandwich, polyurethane foam backed panel having a panelface, a core bonded to the face and a polyurethane foam backside bondedto the core and to frame members.

FIG. 2 is a two layer foam backed panel having a panel face backed by alayer of polyurethane foam that is also bonded to frame members.

FIG. 3 is a supported control panel comprised of a oriented strand board(OSB) to be tested for impact resistance.

FIG. 4 is the control panel of FIG. 3 being tested for impactresistance.

FIG. 5 is a supported foam backed panel identical to the control panelexcept also having a layer of polyurethane foam bonded to the OSB'sbackside.

FIG. 6 is the foam backed panel of FIG. 5 being tested for impactresistance.

FIG. 7 is a foam backed panel with fire spacers embedded in thepolyurethane backing.

FIG. 8 is FIG. 7 showing the fire spacers supporting a panel face aftera fire has melted the polyurethane foam that was also supporting thepanel face.

FIG. 9 is a fire spacer strapped to a frame member after fire has meltedsome of the polyurethane foam of a foam backed panel.

FIG. 10 is a sandwich foam backed panel showing a fire spacer bonded toa panel core and attached to a steel stud.

FIG. 11 shows the front side of the steel stud of FIG. 10 with a holethrough which the fire spacer material was cast to attach the stud tothe fire spacer.

FIG. 12 is a sandwich foam backed panel with a fire spacer having anembedded bolt attached to a wood stud.

DETAILED DESCRIPTION ACCORDING TO THE PREFERRED EMBODIMENTS OF THEPRESENT INVENTION

The inventive subject matter comprises polyurethane foam backed panelswhich are defined as two or more layers of material(s) bonded togetherinto a composite panel with the backside layer being polyurethane foam.These panels have a face on the front side, optional core materiallayer(s) and polyurethane foam bonded to backside of the face or to thebackside of the last core material layer. In essence the panel has aface on the front side and exposed polyurethane foam on the backside. Assuch, the polyurethane foam backed panels may be a sandwich panel with aface material on the front side, polyurethane foam on the backside and acore comprised of any one or more material layer(s) other thanpolyurethane foam. As used herein, the term “foam backed panel” refersto the above described polyurethane foam backed panel.

FIG. 1 shows a sandwich foam backed panel 1 having a face 2, bonded to acore material 3 which is bonded to a polyurethane foam backside 4. Thefoam backed panel 1 is supported by frame members 5 that are embedded inand bonded to the polyurethane foam 4 and thereby bonded to the foambacked panel 1. FIG. 2 shows a two layer foam backed panel 1 comprisedof a face 2 bonded to polyurethane foam backside 4 which also bonds theframe members 5 to the panel. A frame or frame members bonded to a foambacked panel are not considered to be “layers”, even though they arepart of the foam backed panel.

The layers of a foam backed panel are bonded together by adhesion orcohesion with a layer of polyurethane foam as the last or back layer,providing a backing to the prior layers. Adhesion is the action orprocess of adhering, i.e. sticking fast to a surface or substance andcohesion is like molecules sticking together, such as two layers havingthe same binder although different filler materials. Bonded or bondingas used herein shall only refer to an adhesive or cohesive bond.

A binder is any liquid or dough-like material or substance that holds ordraws other materials together to form a cohesive whole by adhesion orcohesion and hardens into a solid. Binders are typically liquefied castmaterials and include polymers, resins, Portland cement and phosphatecements for example. For purposes of this disclosure, a filler added toa liquefied binder and solidifies at some point is a cementitiousmaterial. A filler can be any type of material aggregate, fragments orparticles. Both binders and cementitious materials may be reinforced byvarious methods and materials known in the art. Unless otherwise noted,polyurethane foam referenced herein is a binder and is any self-bonding,liquid applied foam, made from polyurethane, polyisocyanurate or otherchemicals in whole or in part, that is typically cast by spraying orpouring, expands and self-bonds to materials it comes in contact whileit is expanding. While it is a self-bonding, adhesive foam, in somecases it may be desirable to use it in conjunction with a separatebonding material. The polyurethane foam is closed cell and has a densityof less than four pounds per cubic foot and more preferably less than3.2 pounds per cubic foot and even more preferably less than 2.5 poundsper cubic foot.

The composite panel face provides either an exposed finished texture ora base/backer board for an attached finished cladding. The polyurethanefoam backside provides the panel with thermal insulation, an air, vaporand moisture barrier as well as increased load carrying capacity andimpact resistance. The optional core may consist of one or more materiallayers to assist the panel in resisting loads, fire, insects, moistureand other items. The polyurethane foam on a panel's backside isconsidered to be “exposed” and comprises the panel's backside material.The exposed foam may be supported by a frame, although is not covered byanother material such sheathing or a concrete wall. The polyurethanefoam's exposed side may only be covered by a thin film or coating bondedto the foam. Any other foam cover bonded to the foam's backside becomesthe panel's backside and renders the foam as being in the panel's coreand thereby not a foam backed panel.

In one embodiment, a foam backed panel was found to have a dramaticallyhigher impact resistance over an identical panel without polyurethanefoam backing. Impact is herein defined as a high force applied over ashort time period by a moving object, i.e. weighted object, collidinginto a stationary panel. An impact test determines the impact strengthor toughness of a material or panel and for purposes of this disclosureutilizes a falling or swinging object, i.e. weighted object, collidinginto a stationary panel or an object launched from a cannon into astationary panel. The term “applied impact” refers to an amount offorce, as measured in in-lbs or ft-lbs, that is rendered on a panelduring an impact test and results in impact damage, whether it bevisible or not. The terms falling, swinging and launched describedifferent methods by which a weighted object is set in motion.

Impact resistance is determined by a visual comparison of the impactdamage done to two identical panels with the exception that one panel isbacked by polyurethane foam, at least in the area of the impact and thesecond panel has no polyurethane foam backing. The panel without foambacking is a control panel. A greater impact applied to the foam backedpanel is compared to a lesser impact applied to the control panel, afterwhich the impact damage to the two panels is visually compared. Forexample if an applied impact of 300 in-lbs rendered to a foam backedpanel causes less visually ascertained damage than a 150 in-lbs appliedimpact to a control panel, then the foam backed panel has at least 100%more impact resistance than the control panel.

In impact testing a foam backed panel and a control panel it isimportant to be consistent in the testing procedure except for changingthe applied impact rendered against the two panels. Both the controlpanel and the foam backed panel are to be tested with the impact appliedto the panel's front side, over the same given span such that theapplied impact is rendered on both panels at the same specific panelfront side location, e.g. center of the panel width in the center of a12 inch span, with the width being perpendicular to the supported span.The only differences between the two panels and their testing is thatthe foam backed panel has polyurethane foam backing and is tested at ahigher applied impact whereas the control panel does not havepolyurethane backing and it tested at a lower applied impact. Panels maybe impact tested with or without a supporting frame.

A polyurethane foam backed panel has increased impact resistance over anidentical control panel if the foam backed panel's impact damage is lessthan that of the control panel and the applied impact rendered on thefoam backed panel is at least 25% greater and preferably at least 50%greater and more preferably at least 75% greater and even morepreferably at least 100% greater and most preferably at least a 200%greater than the applied impact rendered on the control panel. Impactdamage is defined as cracking, flaking, spalling, indentation, punctureand/or permanent deflection on the panel's front side and, afterremoving the foam from the foam backed panel's backside, the size andheight of any cracks, protrusion or puncture on the backside of thepanel's face or core, if present. Puncture is herein defined as theimpacting object passing through one or more panel layers, althoughfailing to penetrate all of the panel's layers. Impact testing mayresult in a control panel having visible impact damage while a foambacked panel to which it is compared has no visible impact damage.

A foam backed panel must have at least a one half inch thick layer ofpolyurethane foam and preferably at least one inch thick and morepreferably at least two inches thick and even more preferably two andone half inches thick and most preferably at least a three inch thicklayer of polyurethane foam on the panel's backside.

Penetration is herein defined as at least part of the impacting objectfully penetrating all of the panels layers such that either theimpacting object is implanted in the panel and visibly present on thebackside of the panel or the impacting object fell away from orcompletely passed through the panel after impact and leaving atransparent hole through the panel. The degree of panel penetration bythe impacting object is specifically excluded from the determinationimpact damages. Only the previously stated impact damages are to beconsidered whether or not the impacting object penetrated the panel. Assuch the impact resistance of a panel impacted by a 2×4 launched by acannon, for example, can only be determined by a visual inspection ofthe previously stated impact damages caused to the panel and anydistance to which the 2×4 penetrated the panel is irrelevant.

The impact testing herein is applicable to any foam backed panel that isor is to be supported by a frame. For testing comparison purposes anyfull sized foam backed panel or a foam backed panel installed in abuilding may have a foam backed section replicated and fabricated into asmaller sized panel of generally about one to four square feet in size.Such a smaller foam backed panel will be representative of the fullsized or installed panel as long as the same materials, dimensions andgeneral fabrication process are used. A control panel is thenfabricated, identical to the foam backed panel, except without, i.e.less, the polyurethane foam backing. As such the only difference betweenthe foam backed panel and the control panel to be tested is that thefoam backed panel has a layer of polyurethane foam on it's backsidewhereas the control panel does not.

Only the composite panel section of a wall or roof assembly is subjectto impact testing and therefore materials mechanically attached to thecomposite panel section are not to be included in the impact testing.For example brick mechanically attached to a foam backed panel are notto be included in an impact test, although brick bonded to a foam backedpanel does comprise a layer of a composite panel and thereby are to beincluded in an impact test.

Testing has shown that the panel's length and width as well as thepanel's impact location's proximity to a frame member can all affect thedegree of impact damage. As such, it is important that a control panelbe identical to a foam backed panel, except for the foam backing, tohave a true resistance comparison.

Given the large variety of materials and material thicknesses that cancomprise a layer in a foam backed panel, not every such panel willresult in an increased impact resistance. It is highly doubtful that athree inch brick bonded to a backer board will have any greater impactresistance with an additional layer of polyurethane foam. Thesignificance of this impact resistance embodiment is that weaker,thinner and lighter claddings and sheathings can be substituted for themore expensive stronger, thicker and heavier materials. Moreover, alayer of polyurethane foam has the added advantage of providinginsulation and an air, vapor and moisture barrier.

The below testing has shown that two pound density, closed cell, spray(or poured) polyurethane foam of at least 0.5″ thick, when bonded to aback of a cladding or sheathing enables the cladding or sheathing toresist substantially greater impacts. Moreover, the thicker thepolyurethane foam backing, the greater the impact resistance to thepoint that the impact resistance can be several times that of the samesheathing without foam backing.

A first group of testing consisted of ½″ OSB (oriented strand board) cutinto six 6″×8″ panels consisting of two control panels 7, as shown inFIGS. 3 and 4, comprised of only the OSB panel 6 and no polyurethanefoam backing. Four other panels consisted of foam backed panels 1, asshown in FIGS. 5 and 6, and comprised of the same OSB panel 6 backed byof 2″ thick, two pound density polyurethane foam 4 bonded to the OSB'sbackside. As shown in FIGS. 3 and 5 the panels were positioned face-upover a 6″ clear span 8 with 1″ of the 8″ long panel supported bysupports 9 each side of the span 8.

To test the panels for impact resistance, as shown in FIGS. 4 and 6, a 4lb cylinder with a steel tip nose was used as a weighted object 10dropped on each panel from various heights to produce an impact force,or an applied impact on the panels measured in in-lbs and that mayresult in impact damage 20. The impact force was applied to the centerof the area of the panel that was over the span. In the first tests, thetwo control panels 7, were tested with applied impacts of 120 in-lbs (4lb weight dropped from 30 inch height) and a 150 in-lbs impactrespectively to determine the OSB's base impact resistance over the 6″span 8. The 120 in-lbs caused minor cracking on the first controlpanel's front side and no noticeable OSB bending. The 150 in-lbs forcecaused the second control panel 7 to sustain impact damage 20 ofcracking on it's front side and split on it's backside to becomepermanently bent into about a 135° angular shape 21, as shown in FIG. 4.

In subsequent tests, three foam backed panels 1 were each positionedover the same 6″ span 8 and an applied impact of 600 in-lbs, 480 in-lbsand 300 in-lbs was used for the respective tests. The 600 in-lbs testcaused the polyurethane foam 4 backing to split into two sections andseverely cracked and bent the OSB into about a 160° angular shape 21, asshown in FIG. 6. This foam backed panel clearly had more impact damageto the OSB than the control panel's 150 in-lb impact that resulted in a135° bent shape. The 480 in-lbs test resulted in the foam backed panel'sfoam splitting and the OSB cracking, splitting and bending to somewhatless than the 135° bent shape caused to the control panel from a 150in-lb impact.

The third foam backed panel was tested with 300 in-lbs applied impactover the same 6″ span, neither the foam nor the OSB split, bent or evencracked and the only impact damage was a small 0.06″ indentation intothe OSB face. Clearly the impact damage resulting from 300 in-lbsapplied impact to the foam backed panel was less than the impact damagecaused by the 120 in-lbs impact to the control panel and substantiallyless than the 150 in-lbs applied impact to the second control panel.

A fourth foam backed panel test was a second test for the 480 in-lbsapplied impact. This test result was similar to the first 480 in-lbstest, with the foam split the entire panel width perpendicular to thespan and the OSB bent into about a 140° shape, which is slightly morethan the control panel's 135° bent shape from the 150 in-lbs appliedimpact.

From these tests, it is apparent that 2″ of polyurethane foam bonded tothe backside of ½″ OSB enabled the OSB to withstand a 300 in-lb impactbetter than the same OSB without foam backing could withstand a 120in-lb impact. The testing also showed that it would take about 500 in-lbimpact force on an OSB, with 2″ foam backing, to withstand the samedamage incurred by a 150 in-lb impact on the same OSB without foambacking. This represents a 233% increased impact resistance for OSB withthe two inches of foam backing as opposed to the same OSB with no foambacking.

In another set of tests, a 0.25″×6.5″×27″ panel comprised of a magnesiumphosphate binder (MPB), a phosphate cement, to which a filler was addedto comprise a cementitous material, was cast with 2 layers of fiberglassmesh reinforcement. The panel was cut into five sections 5.3″ sectionsresulting in five 0.25″×5.3×6.5″ panels. One MPB panel, selected atrandom, was left without a foam backing, i.e. the control panel, whilethe other four MPB panels were backed by 0.5″, 1″, 1.75″ and 2.5″ ofpolyurethane foam respectively. The five MPB panels were then impacttested over a 4.5″ clear span with an applied impact made to the centerof the area of the panel that was over the span.

When a 25 in-lb applied impact was dropped on both the MPB control paneland the 0.5″ thick foam backed MPB panel, both panels split in half(except for the mesh). A 50 in-lbs applied force to the MPB panel with1″ of foam backing resulted in no panel damage although a 90 in-lbsapplied impact to the same 1″ foam backed MPB panel caused the panel tosplit in half. A 150 in-lbs applied impact to the MPB panel with 1.75″thick foam backing failed to cause the panel to crack or the foam split.Finally, a 300 inch-lb applied impact to the MPB panel with 2.5″ thickfoam backing resulted in only a smudged surface. From this series oftests, it is evident that a 0.5″ thick MPB panel can have it's impactresistance increased by several times with polyurethane foam backing andthe thicker the backing the greater the impact resistance.

In another impact test four 0.5″ thick MPB panels were cut to a 6″×16″size with polyurethane foam bonded to the back of one panel to create afoam backed panel. The other three panels were left as is and served ascontrol panels. The foam backed panel was placed on two supports 14″apart to create a 14″ span and a 180 in-lbs impact was applied on thecenter of the panel over the span. The applied impact caused the foam tosplit and the panel to crack and bend to about a 160° angle. A firstcontrol panel was then positioned on the supports with the same 14″ spanand tested with a 50 in-lbs applied impact which resulted in a lesssevere crack and a panel bent to about 170°. Since the impact damage wasnot as severe as the foam backed panel, a second control panel wastested at 60 in-lbs and resulted in more impact damage than the firstcontrol panel, but still less damage than the foam backed panel. A thirdcontrol panel was tested at 70 in-lbs and resulted in the same degree ofcracking and bent angle as the foam backed panel. As such, the foambacked panel's impact resistance of 180 in-lbs was 257% of that of thecontrol panel that had the 70 in-lbs applied impact.

In another series of impact resistance tests, three 7/16″ thick OSB(oriented strand board) sheathing panels were attached to frames inthree different configurations. The frames consisted of two 93″ wood2×4s studs, spaced 16″ on center (14.5″ clear span) and nailed to a topand bottom 2×4×17.5″ plate. Two panels were configured with the7/16″×16″×96″ OSB sheathing nailed to frames with nail spacing at 8″around the entire OSB perimeter. One of these panels severed as acontrol panel while the cavity of the second panel was filled with 2″thick, two pound density spray polyurethane foam bonded to both theinside face, i.e. backside, of the OSB, and to the frame member's side.A third OSB panel and 2×4 frame were bonded together by the samepolyurethane foam with the exception that 1″ of foam was between the OSBpanel and the top of the frame around the entire perimeter and thefoam's thickness was 2″ inside the frame's cavity, i.e. between thesides of the studs. In other words 1″ of foam was continuous and 2″ offoam was in the cavity formed by frames.

The framed OSB panels were all tested by dropping a 13.5 lb, 2″ steelcylinder with a 1″ steel ball tip welded to the cylinder's end. Thecylinder, with ball tip down, was dropped from various heights onto themidpoint of the OSB panels between the 93″ studs and at least 24″ fromthe end plates. In the first OSB test, the cylinder was dropped from a52 inch height to create a 702 in-lbs (13.5 lbs×52 inches) appliedimpact force on the non-foam backed OSB control panel. In this test onlythe cylinder's ball tip fully penetrated the OSB and the impactpermanently deflected (i.e. bowed) the OSB ⅛″ across the panel's 16″width. In a second test, on a different midpoint location on the samecontrol panel, a 800 in-lb impact force was applied and both the balltip and about 2 inches of the cylinder body fully penetrated the OSB.

The tests were continued on the second OSB panel that had 2″ ofpolyurethane foam backing. In the first and second such tests a 1,400in-lb and a 1,600 in-lb applied impact was made on the midpoint of thefoam backed panel at separate locations. In both cases the impact damagecomprised the full ball tip fully penetrating the OSB panel and into thefoam, although the 2″ cylinder body did not penetrate or even dent theOSB, nor did the OSB become bowed from either applied impact. As suchthe impact damage was less than that of the control panel and becausethe applied impacts were twice that on the control panel, the 2″ foambacked OSB panel had more than twice the impact resistance as the OSBcontrol panel. Moreover, after removing the foam from the backside ofthe OSB, it was visually apparent that the foam backed panel had lessdamage from the 1,600 in-lbs impact than the control panel had with the800 in-lb impact.

Further testing showed that the cylinder dropped to create a 3,100 in-lbforce fully penetrated the 2″ foam backed panel but only penetrated 2″into the 3″ foam backed panel. This again shows that the thicker thefoam, the greater the impact resistance.

A panel is defined as a generally rigid structure, having some amount offlexural stiffness, such as sheathing or cladding that is supported byand covers a frame or frame members. Panels of this invention may beexterior panels, interior panels and of any size or shape. The panel'sfront side, i.e. its face or front skin, may be of any shape and thepanel's backside, may have protrusions or indentations. A panel face orcore may be of any material or combination of materials not hereinexcluded and be of any size. Some examples of panel faces and/or coresare: cementitious materials, sheets and board materials, claddings,sheathing, molded and corrugated materials or any combination hereof toname a few. A composite panel is defined as a panel comprised of two ormore different materials bonded together in layers, such as a claddingor sheathing with a second material bonded to it's backside. Whileplywood, OSB, gypsum board and similar manufactured panels are compositepanels in and of themselves, they may also provide a material layer in afoam backed panel.

Panel may be precast or prefabricated, in whole or in part, before beingmoved to their final installed position or they may be completely castor fabricated in place, i.e. in their final installed position. Forexample a panel's face and core layers may be precast and then shippedto the building site where it is installed and the polyurethane foambacking layer added. The term cast or casting shall include pouring andspraying any material that can be poured or sprayed. Panels may beattached to a previously installed frame or a frame may become part of apanel if the frame has one or more panels attached or bonded to itbefore being installed, i.e. becomes part of a building. For example aprecast panel may have a frame attached before the panel is installedand the frame becomes part of the panel.

Cladding is defined as any panel, material or combination of materialsused to provide a front or outside cover for a panel or a framedstructure. Cladding may be of any size and shape and of any materialincluding panels, panel skins, siding, tiles, bricks, stones, shingles,aggregates, stucco, fiberglass, coatings, film, paint and othermaterials and even a foam's integral skin if the skin has a modulus ofelasticity different than the foam's core. Coatings, film and paint areonly considered a cladding if the total dried thickness is greater than10 mils (0.01″). The cladding may be a panel itself, such as plywood ora foam board or may it be a part of a panel such as a coating applied toa foam board or a laminated panel. The cladding has a face, i.e. frontside or exposed side, and a backside that is generally unexposed and isattached to a backing material and/or a frame.

Sheathing is herein defined as a separately installed panel or othercovering over a frame that is covered by a separately installedcladding. Since a dried coating, film or paint of 10 mils (0.01″) orless are not claddings, sheathing covered by these materials is acladding, unless the sheathing is covered by a separate cladding.Alternatively, if coating, film or paint of any thickness are applied toa separately installed panel which is not covered by a cladding, theresulting coated, film covered or painted panel is a cladding. When aframed structure has both a sheathing covered by a separately installedcladding, the combined sheathing and cladding are a cover.

A frame is any rigid structure formed of one or more relatively slenderpieces, i.e. frame members, and used to support attached panels.Individual frame members have two ends, a front and back edge that isparallel to the cladding or sheathing and two or more sides that aregenerally perpendicular to the cladding or sheathing. Frame members mayor may not be in direct contact with one another to form a frame.Cladding or sheathing may be in direct contact with a frame and bondedor fastened to a frame. A frame may be embedded in a polyurethane foamlayer to support a foam backed panel when two or more frame members arebonded to and embedded in the polyurethane foam layer to a depth of atleast one half inch.

In another embodiment the foam backed panel is a refractory sandwichbuilding panel comprised of a face, an insulating refractory corematerial and a polyurethane foam backing. One of polyurethane foam'sweaknesses is that it has a low tolerance to heat and begins degradationat around 250° to 300° F., which is far below fire temperatures of 1000°to 2000° F. and higher. Therefore, especially in cases where a foambacked panel is attached to a building by the panel's polyurethane foambacking bonded to the building's frame, precautions must be taken toprotect the foam and/or building from fire.

ASTM E119 is a wall assembly fire test requiring at least part of a wallstructure to remain in place for one or more hours when subjected to afire. Specifically, ASTM E119 is a pass-fail test based on a wallassembly's, including a wall panel's, ability to prevent a water streamfrom penetrating into the wall's interior side immediately after thewall's exterior side has been subjected to fire flames, hightemperatures and gases for 60 minutes or longer. The test is for one,two, three and four hours and determines whether some portion of theassembly or panel remains standing as a barrier capable of preventingthe water stream from passing through the wall. Under such a test it isnot uncommon for much of the wall assembly to be destroyed or severelydamaged from the fire.

Using ASTM E119 as a basis to determine fire protection, it has beenfound that an insulating refractory core material, when formed as aslab, may be of such a thickness that it's thermal resistance prevents afire's temperature on it's front side from increasing on it's backsideto a temperature that causes the foam bonded to the slab's backside frommelting. Thermal resistance is the temperature difference between theslab face and backside that induces a unit heat flow rate through a unitarea of the slab.

Although, simply because an insulating refractory material has thethermal resistance to substantially reduce the temperature on it'sbackside from the heat of a fire on it's face, i,e. front side, does notnecessarily prevent foam bonded to the backside from melting. Testinghas shown that when polyurethane foam is bonded to the backside of aslab having a lower thermal resistance than the foam, a temperatureresistant barrier is created at the slab's backside. Basically the foamprovides an increased thermal resistant which causes the heat to becometrapped or “bottled up” at the slab's backside and the temperaturebegins to rise since the heat's flow is severely restricted by the foam.As shown in the below test results, any heat flowing from the slab'sface to backside encounters substantial resistance when it reaches thepolyurethane foam bonded to the backside and the resulting increasedtemperature at this core/foam joint must be accounted for in determiningthe insulating refractory core material's thickness.

For example, a one inch thick slab comprised of a magnesium phosphatebinder with a 3:1 by weight binder to vermiculite filler was tested. Ina first test, the one inch slab was subjected to a flame ranging from1740° F. to 1810° F. applied the slab's face over 60 minutes, while theslab's backside temperature was recorded. Beginning at the ambienttemperature of 82° F. the backside's temperature increased to about 117°F. over the first 20 minutes and then remained within two degrees of117° F. for the next 40 minutes.

In a second test of the same one inch thick slab, a two inch thick twopound density polyurethane foam was bonded to the slab's backside. Inthis test a thermometer was inserted through the foam to the slab'sbackside to record the temperature at the slab/foam joint. As thetemperature of the flame applied to the slab's face was raised fromabout 1200° F. to 1750° F. over a 60 minute period, the temperature onthe slab's backside increased from an ambient 85° F. to 197° F. in 30minutes and then leveled off at about 207° F. over the final 30 minutes.After 60 minutes the fire was extinguished although the slab's backsidetemperature continued to rise for about 6 minutes reaching a peak of230° F. When the foam was cut away from the slab's backside it wasrevealed that the 230° F. was insufficient to melt any of the foam.

In comparing these two tests, the existence of the foam bonded to theslab's backside caused the temperature to buildup to about twice that ofan open aired backside. As such, it is apparent that the temperature onthe slab's backside can be considerably higher when foam is bonded tothe slab's backside as opposed to an open aired backside. Moreover, thegreater the difference between the thermal resistance of the slab andfoam the greater the heat buildup on the slab's backside. As such,simply knowing a slab's thermal resistance will not necessarilydetermine whether or not foam bonded to the slab's backside will melt atany given temperature. Only after testing specific slab/foamcombinations can it be known whether or not a fire applied to the faceof a slab, of a certain material and thickness, is sufficient to preventa certain foam, bonded to the slab's backside, from melting. No suchtesting or relationships have previously been established.

A similar test was conducted on a 1.1″ thick slab comprised of magnesiumphosphate binder with an expanded clay filler and two inches ofpolyurethane foam bonded to the slab's backside. A 1,700° F. flame wasapplied to the slab's face for 60 minutes and the temperature on theslab's backside was recorded. The backside's temperature began at 80° F.ambient temperature and rose to 213° F. over the 60 minutes after whichthe flame was extinguished. While the backside's temperature continuedto increase to 236° F. over the next 10 minutes, this temperature wasinsufficient to cause any of the foam from melting as determined whenthe foam was cut away from the slab.

In another test for a two hour fire rating pursuant to ASTM E119, a twoinch thick slab comprised of magnesium phosphate binder with an expandedclay filler was mixed with water and cast into a form. After curing, twoinches of polyurethane foam was bonded to the slab's backside and athermometer placed through the foam to the slab's backside. A fire waspositioned on the slab's face with temperatures beginning at 1100° F.and increasing to 1910° F. over 120 minutes, consistent with temperatureincreases prescribed by ASTM E119. The temperature on the slab'sbackside was recorded beginning at 82° F. ambient temperature andincreased to 206° F. at 120 minutes, at which time the flame wasextinguished and the temperature began to decrease. After the foam wascut away from the slab, it was revealed that none of the foam melted. Asa result a two inch thick insulating refractory material slab preventedthe melting of polyurethane foam bonded to the slab's backside.

Several similar tests were done using different face materials as wellas different lightweight insulating fillers including vermiculite,perlite and expanded shale as well as different binders such as sodiumsilicate. In all cases the polyurethane foam bonded to the insulatingrefractory material core restricted the heat flow at the slab/foam jointwhich resulted in a much higher temperature than was recorded when theslab's backside was open aired.

In another test, a one inch thick mineral wool was tested with andwithout polyurethane foam bonded to it's backside. The Roxul #40320mineral wool is rated with a 4.0 R-value and a thermal conductivity ofabout 0.04 W/(m K). In a first test, without polyurethane foam bonded toit's backside, a 1700° F. flame was applied to the mineral wool's faceover 60 minutes and the temperature on the mineral wool's backsideincreased from 82° F. to 204° F. over the 60 minutes. In a second test,the same mineral wool had two inches of polyurethane foam bonded to it'sbackside. This mineral wool's face was then subjected to a flamestarting at 1200° F. that was increased to 1600° F. over 45 minuteswhile the temperature on the mineral wool's backside was recorded. Thebackside's temperature rose from an ambient 92° F. to 400° F. over the45 minutes at which time the fire test was stopped due to the foam'sapparent melting. When the foam was cut away from the mineral wool, a0.75″ depth of melted foam was revealed.

This test revealed that the polyurethane bonded to the mineral wool'sbackside severely restricted the heat flow and thereby trapped the heatresulting in the polyurethane foam melting. Moreover, despite having a4.0 R-value and a thermal conductivity of about 0.04 W/(m K), themineral wool was insufficient to prevent the foam from melting on it'sbackside.

In another test a one inch thick panel of calcium silicate, manufacturedby Johns Manville, having a thermal conductivity of about 0.10 W/(m K)was fire tested with 2″ of foam bonded to it's backside. Temperaturereadings were taken every 10 minutes on the front face and the panelsbackside, inside the foam. In this test the face temperature reached1720° F. at 50 minutes before ending at about 1690° F. at 60 minutes, atwhich time the backside temperature was 324° F. and continued toincreased to 346° F. over 8 minutes after the fire was extinguished. Inthis case only about ⅛″ of the foam melted.

FIG. 1 shows a sandwich foam backed panel 1 with a slab face 2, a core3, which may be an insulating refractory material, and polyurethane foam4 on the panel's backside that bonds the panel to frame members 5. Whileit is well known that the thicker the core 2, the greater it's thermalresistance, thicker cores cost more, are heavier and encroach onvaluable interior floor area. As such, it is preferable to have as thina panel core as possible to prevent the foam backing 4 from melting whenthe slab face 1 is subjected to certain degrees of fire.

While it is well known that material thickness is directly correlated tothermal resistance of a slab, the more important issue is the corematerial's fire resistance capacity. In other words, what is the minimumcore thickness needed for a particular insulating refractory material toprevent the foam bonded to the slab's backside from melting when theface of the slab is subjected to one, two or three hour firetemperatures. Once an insulating refractory material's fire resistancecapacity is known for a given fire rating, any additional materialthickness serves no fire resistance purpose.

Insulating refractory materials are herein defined as a type ofnon-metallic material having an insulating R value of 0.5 or greater aswell as those chemical and physical properties that make them applicablefor structures, or as components of systems, that may be exposed toenvironments above 1,000° F. (811K; 538° C.).

There are a number of well known refractory binders that can be combinedwith various known high temperature resistant insulating materials,however there is no such known combination that meets the requirementsof being relatively thin, impact resistant and sufficiently insulativeto prevent foam from melting within a certain time duration. Examples ofrefractory binders are calcium aluminate cements, magnesium phosphatebinders other phosphate based binders, sodium silicate (aka waterglass), various blends and more. When these and similar refractorybinders are mixed with fillers such as lightweight aggregate materialsincluding vermiculite, perlite, extend-o-spheres, bubble alumina andexpanded clay, shale and slate they result in insulating refractorymaterials that provide thermal insulation. Such compositions typicallyhave low density, low thermal conductivity and inferior mechanicalstrength to that of conventional castables. As used herein, the term“magnesium phosphate” is a binder mixed with one or more fillers and mayinclude additives and be reinforced.

The fire resistance rating of some insulating refractory materials maybe changed by altering the binder-to-insulating material composition orthe density of the insulating refractory material. In addition, thebuilding panel's face and core layers may consist of the same or adifferent insulating refractory material. For example, all or part of arefractory material core may have a non-insulating filler, such as apowder, sand and/or rock to increase the panel's impact resistance, or apanel's face may be a refractory material comprised of a refractorybinder with a non-insulating filler.

For purposes of this disclosure, an insulating refractory material'sfire resistance capacity for a one hour fire ratings pursuant to ASTME119 is limited to about 3″ or less core thickness, and preferably about2.5″ or less core thickness and more preferably about 2″ or less corethickness and even more preferably about 1.5″ or less core thickness andmost preferably about 1″ or less core thickness. For a two hour fireratings pursuant to ASTM E119 the core's thickness is preferably about4″ or less thickness, and more preferably about 3″ or less thickness andeven more preferably about 2.5″ or less thickness and most preferablyabout 2″ or less core thickness. For a three hour fire ratings pursuantto ASTM E119 the core's thickness is preferably about 5″ or lessthickness, and more preferably about 4″ or less thickness and even morepreferably about 3.5″ or less thickness and most preferably about 3″ orless core thickness. For purposes of the above thicknesses the term“about”shall be within an additional half inch of core thickness.

In another embodiment special fire spacers are embedded in the foambacked panels to enable the panel to resist fire, especially inapplications where polyurethane foam bonds the panel to a supportingframe.

Testing has shown that a panel comprised of a magnesium phosphate binder(MPB) with fiberglass reinforcement, can withstand 2,000° F. heat andflames for more than one hour. In so doing the MPB panel remains intactand prevents flames from penetrating through it, although, in a foambacked panel, the high temperature can melt some or all of anypolyurethane foam bonded to the MPB panel's backside. As would beexpected, the depth of the foam melted varies with the panel's materialcomposition and thickness. However, it was found that the increasedtemperature on the MPB's backside may limit the melting foam to that onor closest to the MPB and not affect the foam one, two or three inchesaway from the MPB. From this recognition a fire resistant spacer wasdeveloped to bridge this melting zone and thereby bond the MPB to theunaffected foam and to the building frame.

FIG. 7 shows a foam backed panel 1 having a cladding as a panel face 2attached to a building's frame members 5, i.e. studs, by polyurethanefoam 4 adhesively bonded to both the panel face's backside 11 and to theframe members 5. Also shown is a fire spacer 12 attached to the face'sbackside 11 and embedded in and adhesively bonded to the polyurethanefoam 4. The frame members 5 are shown as partially embedded in andbonded to the polyurethane foam 4. In this configuration the fire spacer12 is adhesively bonded to the frame members 5 by the polyurethane foam4 which provides a thermal break between the panel face 2, fire spacer12 and the frame members 5.

FIG. 8 shows the effect on the foam backed panel 1 of FIG. 7 after heat27, generated by a fire, is placed against the panel's face 2 for anextended period of time. The heat moves through the panel face 2 and canmelt the foam 4 on the panel face's backside 11 for a distance, which isreferred to as a melting zone 28. This creates an open space between thepanel's face 2 and the remaining polyurethane foam 4 beyond the meltingzone 28, which was not affected, i.e. melted, by the heat 27. The widthof the melting zone 28 is determined by the fire's temperature, thepanel face's 2 thermal resistance, the foam's 4 melting point andwhether or not the heat was fully contained.

FIG. 8 also shows the unaffected, remaining foam 4 bonded to the firespacer 12 and to the frame members 5. Assuming the foam bond issufficiently strong, this configuration will temporarily support thepanel face 2 in place for at least one or more hours as required by ASTME119.

If is important that the bond between the panel face 2 and the firespacer 12 be able to withstand the fire temperature by either heatresistant adhesives or a fire spacer 12 with sufficient bonding strengthcast directly onto the panel face's backside 11.

In another configuration, FIG. 9 shows a connecting object 16 embeddedor otherwise attached to the fire spacer 12 and extending from firespacer 12 to attach to the frame member 5 with a fastener 17. Theconnecting object 16 may be anything from a partially embedded strap toan embedded nut to which a bolt attaches the frame, to a cast bindermaterial. Such a configuration is sufficient to temporarily hold thepanel face 2 in place during a fire. In FIG. 9, it is not necessary thatthe fire spacer 12 extend to the foam 4, as long as the connectingobject 16 is sufficiently stiff and can withstand whatever temperatureexists between the fire spacer 12 and the foam 4.

In FIGS. 10 and 12, the fires spacers 12 are bonded directly to a panelcore 3 and to frame members 5. In FIG. 10 the frame members 5 are steelstuds having a flange 14 through which the fire spacer 12 is bonded bycasting the fire spacer material through a hole 13 on the steel stud'sflange 14 facing the panel core 3 or panel face as the case may be. Astay-in-place foam form (not shown) may be placed between the steel studand panel core 3 to contain the fire spacer material as it is cast inplace. FIG. 11 shows the steel stud frame member 5 of FIG. 10 having ahold 13 punched through the stud's flange 14 with the hold 13 smallerthan the flange 14. Since the fire spacer 12 cast material inside thesteel stud is wider than the hole 13, the fire spacer 12 becomesembedded in the steel stud for a solid and strong connection.

FIG. 12 shows a similar configuration to FIG. 10 except the frame memberis wood in FIG. 12 and has a bolt 15 screwed into the side of the woodframe member 5 that is also embedded into a cast-in-place fire spacer12. Again, a stay-in-place foam form (not shown) may be used for castingthe fire spacer 12 onto the panel core 3 and of sufficient height toembedded the bolt 15.

Fire spacers may be any shape or material that can withstand a fire'stemperature and have a thermal conductivity of less than 2 W/(m K) andpreferably less than 1 W/(m K). Materials having a higher thermalcoefficient are specifically excluded as fire spacers due to theirability to cause thermal bridges through the insulation. Although, asstated above, metal straps, bolts and fasteners may be used to attach afire spacer to a frame member.

In another embodiment the foam backed panels are precast and comprisedof two or more or three or more layers of cast binder materials and/orcementitious materials. Magnesium phosphate and polyurethane foam arecomplimentary materials in that when combined the resulting compositepanel overcomes each material's weaknesses while enhancing theirstrengths. For example, magnesium phosphate is harder, more durable,fire and insect resistant, and can be used as a panel face, none ofwhich applies to polyurethane foam, whereas polyurethane foam has highthermal resistance and is an air, vapor and moisture barrier, none ofwhich applies to magnesium phosphate. On the other hand, both materialsare relatively light weight, have excellent bonding strengths, are waterresistant and setup very quickly. The result is a comprehensive wall orroof building panel, comprised of only two materials, and can bemanufactured very quickly.

From a manufacturing perspective is is now possible to precast and thenhandle a sandwich building panel in less than one hour. For example,either a prefabricated cladding laid face down or a magnesium phosphatecementitious material cast on a form as a panel's face can have a panelcore layer of magnesium phosphate binder with an insulating refractorymaterial filler, for example, cast on the panel face's backside within afew minutes. The core layer is followed, within 20 minutes, by a panelbackside layer of polyurethane foam applied over the panel corematerial. The foam expands and hardens in minutes to enable a finishedsandwich panel to be removed from the form and handled in less than 60minutes from placing the panel face. During expansion the foam mayoptionally self-bond to a frame suspended above the applied foam.

Various additives and reinforcements may be added to the magnesiumphosphate and the polyurethane foam and additional material layers mayalso be added such as spraying a thin film on the backside of the panelface or panel core to further resist moisture. In all cases it isimportant to ensure the sprayed material adequately bonds to the layeron which it is sprayed and also allows the next layer to adequately bondto the film.

In another configuration a Portland cement binder with various fillersto comprise a cementitious material may be cast onto a form as a panelface followed by a layer of magnesium phosphate cementitious material asthe panel core and finally a cast polyurethane foam panel backside. Inthis case both the magnesium phosphate and the polyurethane foam selfbond to the prior materials within minutes of the prior material'scasting. However, the Portland cement panel face will require a muchlonger setup time before the panel can be removed from the form.

Precasting the various materials may be done by pouring or spraying thematerial in a generally horizontal form or by spraying the material ontoa tilted or vertical form. The cast materials may be self-bonding to thematerials on which they are cast or an adhesive material may be appliedbetween cast layers.

Another example of a precast foam backed panel is a multi-layered corecomprised of the same binder that has different fillers in the differentlayers. For example a magnesium phosphate binder may use a quartz or flyash filler in a front panel layer to increase a panel's impactresistance, and then use an insulating filler in a second core layer forfire resistant purposes. The second core layer may be immediately caston a still wet first core layer and the common binder will bond the twolayers together despite different fillers. As such the different fillermaterials result in the layers having different properties.

From the description above, a number of advantages of variousembodiments of the polyurethane foam backed panel become evident:

(a) The inventive subject matter enables thinner, weaker and lightercladdings or sheathings to have substantial impact resistance by bondingan insulating foam material to their backside.

(b) Despite causing heat to be restrained and buildup as it encounters apanel backside layer of polyurethane foam, a relatively thin one inchlayer of insulating refractory material has sufficient thermalresistance to prevent the foam, bonded to it's backside, from melting.

(c) A refractory insulating material such as magnesium phosphate backedby polyurethane foam produces a simple fire resistant foam backed panelcapable of withstanding the heat from a fire for more than one hour.

(d) Fire spacers as small as 2″×2″ can sufficiently bond a refractorymaterial panel face and/or core, in a foam backed panel, to framemembers such that the panel face and/or core remains in place during afire to attained a one or more hour fire rating pursuant to ASTM E119.

(e) Fire spacers can bond a panel to a building frame without causing athermal bridge.

(f) Refractory materials as thin as 0.25″ thick can be used as a foambacked panel's face and/or core material to attain a one or more hourfire rating when bonded to a building frame with fire spacers.

(g) Insulating refractory materials in a foam backed panel enableslighter fire rated panels.

(h) Precast foam backed panels may be manufactured, removed from a formand handled within as little as one hour.

(i) Precast foam backed panels may use a single binder in two or morelayers with each layer comprised of a different filler to product adifferent material properties.

Although the description above contains many specifications, theseshould not be construed as limiting the scope of the embodiments but asmerely providing illustrations of some of several embodiments. Thus thescope of the embodiments should be determined by the appended claims andtheir legal equivalents, rather than by the examples given.

I claim:
 1. A polyurethane foam backed panel having increased impactresistance comprising: a. a foam backed panel with two or more layers ofmaterial(s) bonded together in a composite panel with at least one layercomprised of a cementitious material and a backside layer consisting ofat least one half inch thick polyurethane foam, and b. said foam backedpanel having impact damage rendered by an impact test with a firstapplied impact made at a specific panel front side (39) location over agiven span, and c. a fabricated control panel consisting of an identicalto said foam backed panel, less said backside layer of said polyurethanefoam, and d. said control panel having said impact damage rendered bysaid impact test with a second applied impact made at said specificpanel front side location over said given span, and e. said firstapplied impact is at least 25% greater than said second applied impact,and f said impact damage of said foam backed panel is less than saidimpact damage of said control panel as determined by a visualcomparison, whereby said polyurethane foam backed panel has increasedimpact resistance.
 2. The foam backed panel of claim 1 wherein saidfirst and second applied impacts are made by an identical weightedobject set in motion the same way.
 3. The foam backed panel of claim 1comprising a cementitious material panel face backed by said foam. 4.The foam backed panel of claim 1 comprising a cementitious material corebacked by said foam.
 5. The foam backed panel of claim 1 wherein saidcementitious material is reinforced.
 6. The foam backed panel of claim 1comprising a supporting frame embedded in said foam backside layer. 7.The foam backed panel of claim 6 comprising a precast panel.
 8. The foambacked panel of claim 6 fabricated in place.
 9. A method of testing anincreased impact resistance of a polyurethane foam backed panelcomprising, a. rendering an impact test with a first applied impact,made at a specific panel front side location over a given span, on afoam backed panel having two or more layers of material(s) bondedtogether into a composite panel with at least one layer comprised of acementitious material and a backside layer consisting of at least onehalf inch thick polyurethane foam and resulting in impact damage on saidfoam backed panel, and b. fabricating a control panel identical to saidfoam backed panel, less said backside layer of said polyurethane foam,and c. rendering an impact test with a second applied impact on saidcontrol panel made at said specific panel front side location over saidgiven span and resulting in said impact damage and said first appliedimpact is at least 25% greater than said second applied impact, and d.visually comparing said impact damage on said foam backed panel withsaid impact damage on said control panel, and e. finding said impactdamage on said foam backed panel is less than said impact damage on saidcontrol panel, f. whereby said polyurethane foam backed panel hasincreased impact resistance.
 10. A multi-layered polyurethane foambacked panel having increased impact resistance comprising: a. a foambacked composite panel, with at least one layer comprised of acementitious material and a backside layer of at least a one half inchthick polyurethane foam, and said panel having impact damage resultingfrom an impact test with a first applied impact made at a specific panelfront side location over a given span and b. an identical, fabricatedcontrol panel, less said polyurethane foam layer, having said impactdamage resulting from said impact test with a second applied impact madeat said specific panel front side location over said given span, and c.said first applied impact is at least 25% greater than said secondapplied impact and said impact damage on said foam backed panel is lessthan said impact damage on said control panel, as determined by a visualcomparison of said impact damages, d. whereby said foam backed panel hasincreased impact resistance.
 11. The foam backed panel of claim 10wherein said first and second applied impacts are made by an identicalweighted object set in motion the same way.
 12. The foam backed panel ofclaim 10 comprising a precast panel.
 13. The foam backed panel of claim10 fabricated in place.
 14. The foam backed panel of claim 10 comprisingone or more layers of cast binder materials.
 15. The foam backed panelof claim 10 wherein said cementitious materials comprise of refractorymaterials.
 16. The foam backed panel of claim 10 comprising a supportingframe embedded in said foam backside layer.